A friend of mine had an unlocked GSM phone he uses in Canada and went to the UK. He picked up a SIM card and was able to make calls.

Now we have 99 buck good enough smart phones and under 20USD phones that call and text all we need is a carrier.

I'm not sure if there are no contract systems in your city but my friend did so in London.

http://www.amazon.co.uk/gp/bestsellers/electronics/356496011/ref=pd_zg_hrsr_ce_1_5_last finds you call them SIM FREE. I see BLU, DOOGEE and the others for sale there for the usual prices.